Lamp mounting



June 16, 1931. c. H. LARSON 1,810,666

LAMP MOUNTING Filed Aug. 31, 1929 15 26 J9 U r 29 1 Patented June '16, 1931 UNITED STATES.

PATENT OFFICE CARL LARSON, OF ELKHABT, INDIANA, ASSIGNOR TO THE ADLAKE COMPANY, A

CORPORATION OF ILLINOIS LAMP MOUNTING Application filed August 31, 1929. Serial No. 389,847.

' The principal'objects of this invention are to provide improved means for focusing a lamp with respect to the lens or reflector with which it is associated and to protect the lamp from injury due to excessive vibration and jarring.

Other and further objects and advantages will become apparent as the disclosure proceeds and the description is read in conjunction with the accompanying drawings, in which: V i

Fig. 1 is a plan view of the improved lamp mounting; and

Figs. 2 and 3 are side elevations of the same.

In the preferred embodiment of this invention, the base 10, which may be of any suitable shape, is provided with upstanding studs or posts 11, 12 and 13 which carry an annular plate 14 of insulating material, such as bakelite, held in roper spaced relationship from the base 10 By suitable nuts 15. The lower ends of the posts 11, 12 and 13 which extend through the base 10 are rounded, as at 16, forming a seat for the lamp mounting. A connecting bolt 17 securesand firmly seats the improved lamp mounting to the outer shell or casing 18 (only partly shown) of the signal lamp.

A transformer 19 of conventional form is suspended from the annular plate 14 by suspension bolts 20 and 21 which are provided with spacer sleeves 22 and 23 respectively for rigidly holding the transformer in place. The transformer 19, however, is not essential in this construction it being used only in case it is necessary to adapt the available current to the requirements of the bulb.

The upper portions of the posts 11, 12 and 13 extend above the upper face of the annular plate 14: and are threaded to receive thumb nuts 24, 25 and 26. These nuts are provided with a grooved neck portion 30, preferably V-shaped in cross section, to receive the outer curved extremity of coiled springs 27, 28 and 29 respectively, the inner ends of which support a lamp socket 31. These springs are under sufficient tension so as to support the lamp socket in substantially the same plane as the coil springs.

Suitable binding posts 32 and 32 areprovided on the annular plate 14 for securing the lead-in wires and the wires connecting with the transformer and the lamp socket.

The wiring need not further be described since it is asis usual in such constructions.

It is essential in railway signal lamps that thefilament of the lamp be accurately posi tioned at the focal point of the associated lens. In the present case this is accomplished by adjustmentof the thumb nuts 24, 25 and 26 from'whichthe lampsocket tll is. suspended by the springs 27 28 and 29, the adjustment being. continued until the filament 38 of the lamp 33 coincides with the focal point of the lens." A vertical adjustment is obtained by simultaneously screwing the thumb nut's 2 i, 25 and 26 an equal distance up or down the posts while a lateral adjustment is obtained by screwing one of the thumb nuts at a time; This adjustment is of the familiar universal type which permits of adjustment: of the lamp filament to any given point within alimited range. Inthis' way. the lamp filament 32 may be accurately. positioned at the focal point of the lens.

The adjustment is reliably maintained by the'friction'between. the encircling Wire loop of: the spring and the nut, increased by the spring tension and the binding of the wire within the V-shaped groove in the nut. The" use of locknutsisavoided, a consideration of importance'especially in signal lamps inwhic-hi accessto the adjusting mechanism is obtained only through. restricted openings in the casing. rendering the use of tools-ab most impossible. without drawing the support from the casing.

Inasmuch as the lamp is suspended freely by. the springs which are under tension there is-little'or no danger of the filament 33 being injured: or broken by excessive'vibration of the lamp mounting.

Furthermorethe constructionais such that the resilient mounting: of the lamp socket does not interfere with or affect. the focusing as I of the lamp with respect to its associated lens and the displacementof the lamp due to vibration is but momentary the lamp film ment returning to its initial position at the focal point of the lens almost immediately.

The improved lamp mounting has been described as employed in a railway signal lamp but it is obvious that may advantageously be used in various other lamp structures wherein the universal adjustment of the lamp and the resilient mounting thereof are desirable features.

It is, oi course, apparent that various changes and modifications may be made in the detail of the lamp mounting illustrated ithout departing from the spirit of this invention as expressed in the appended claims forming apart hereof.

I claim as my invention:

1. A lamp mounting comprising in com bination a base, a plurality of posts rising from said base, and threaded at their upper ends, a lamp socket positioned between said posts, springs extending between said posts and said socket "for supporting the latter, thumb nuts for said posts, said nuts being adapted to carry the outer extremities of said springs for perniitting a universal adjustment ot' the lamp socket.

2. A lamp support comprising in combination, a plurality of upstanding posts threaded at their upper ends, thumb nuts for said posts, a lamp socket positioned centrally of said posts, and resilient elements extending between said thumb nuts and said lamp socket for supporting the latter substantially in a plane with said resilient elements.

3. A lamp support comprising in combination, a plurality of upstanding posts threaded at their upper ends, grooved thumb nuts cooperating with said threaded portion of said posts, and a lamp socket positioned centrally of said posts and springs extending between said lamp socket and said nuts for supporting the socket, the outer curved extremities of the springs encircling said grooved portion of the nuts and furnishing a frictional locking of the nuts in adjustment.

4. A lamp support comprising in combination, a plurality of upstanding posts threaded at their upper ends, thumb nuts cooperating with said threaded portion of said posts, a lamp socket positioned centrally of said posts and springs extending between said lamp socket and said nuts for supporting the socket, said thumb nuts being provided with an annular V-shaped groove for receiving the outer curved extremities of the springs for furnishing a. frictional locking of the nuts in adjustment.

In a lamp structure of the type includ- 5. ing a lamp adapted to be positioned at the focus of a condensing lens or reflector, the

CARL H. LARSON. 

